Vehicles such as, but not limited to, recreational vehicles including all-terrain vehicles (ATVs) and utility task vehicles (UTVs) implement belt operated continuously variable transmission (CVT) or dual clutch transmissions. Vehicles that implement CVT typically require the vehicle to stop before shifting between low range and high gear range. However, it is not uncommon for operators to not come to a complete stop when shifting between low and high gear ranges. Some newer systems allow for shifting from low to high at higher speeds however noise, vibration and harness (NVH) factors and durability are very poor.
In a typical CVT system, to make a shift from low to high, the throttle is let off and a shift handle is moved from low to high. When this occurs a shift dog is disengaged from low into a short neutral band and then is slide into high. Because of a gear ratio difference between low and high, the high gear shift dog is going at a reverse shaft revolutions per minute (RPM) while the high gear is going at a different RPM. The RPM difference is dictated by the ratio difference between high and low and the input shaft RPM. An associated second clutch is also going at low gear RPM upon disengagement of low. Because of this RPM difference, there is a loud audible “clunk” that occurs between shift dogs when high is engaged. Once the shift happens, the secondary clutch, which was connected to the vehicle ground speed at a low transmission ratio, is now connected to ground in high transmission ratio. The energy required to change the clutch RPM results in the undesirable clunk when making this shift.
For the reasons stated above and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for and effective and efficient shift on the fly transmission.